RECENT OBSERVATIONS COMPARING MINIMUM TILLAGE AND CONVENTIONAL
PLANTING PROCEDURES IN THE NORTH FLORIDA AREA

Dale Sechler, W. H. Chapman, Ralph Lipscomb, W. K. Robertson-1

Due to the high costs involved in conventional seedbed preparation for corn and
soybeans and an increasing cost as well as shortage of labor, much interest has been focused
on the possibilities of a once-over planting operation. New machines are becoming available
which enable the farmer to prepare the seedbed, incorporate the fertilizer as well as the
herbicide or insecticide if needed, and plant the seed in one operation. Also if
cultivation is needed after emergence, some machines can be adapted for this use. This
reduces the capital investment in machinery and the high costs of going over the land in
the many operations involved in conventional seedbed preparation. Since less time is
involved in the planting operation, the crop can possibly be seeded at a more optimum time
and moisture loss can be reduced. With the advent of multiple cropping systems less time
is lost in moving from one crop to another in the cropping sequence.

Two types of once-over planting methods have been compared at Quincy and Marianna.
One planter, known as a mulch type, has a middlebuster followed by a pair of rotary mould
boards which throws the surface residue to the middle of the row and away from the area
where the seed is placed. Some fertilizer needs to be placed in the row at seeding since
anything on the surface is moved to the area between the rows. Since most weed seed are
thrown away from the row and soil in the middles is left rough, conditions for weed seed
germination and growth are less favorable. The other type of planter, known as a tilther,
has rotary type kni-es which work up an area from a few inches wide, to the entire row
wtdth, depending upon the desire of the operator. All surface material is incorporated into
the soil and the fertilizer or other materials can be mixed in the soil during the operation.
The rotary type knives can later be moved to the center of the row and used in cultivating
the young crop.

Conventional planting methods will normally involve at least three operations in
planting either plowing, disking at least once and planting or disking at least twice and
planting. Cultivation then is done with an entirely different machine either a rotary
hoe and a cultivator with sweeps or both.

Soybeans were planted after small grain at Quincy in 1966 to compare the results from
different planting techniques (Table 1). Burning the small grain straw prior to planting
did not affect the soybean yield although better stands were obtained where this practice
was followed in two different experiments. Yields were slightly higher where planted by
conventional methods in experiment no. 2, but this increase would probably no more than
cover the increased planting costs.

Soybeans were planted after small grain for two years at Marianna comparing the mulch
with conventional planting methods (Table 2). Yields from the two planting methods were not
significantly different.

Corn was planted in oat residues at Marianna in 1966 comparing the mulch and
conventional planting methods with the mixed fertilizer applied broadcast or in the row and
sidedressed at four nitrogen levels (Table 3). The Marianna area was extremely dry during
the growing season. The broadcast fertilizer was associated with slightly higher yielMd
than fertilization in the row. Where fertilizer was placed in the row, mulch planted corn
yields were equal to conventionally planted. There was little response to nitrogen in this
experiment, perhaps due to the dry weather.

Corn was planted at Quincy also in 1965 comparing mulch with conventional planting
methods (Table 4). A slightly higher yield was obtained where the mulch planter wto used.
Statistically the method of planting affected both yield and ear weight. There v~a a
significant response to nitrogen sidedressing with the maximum yield estimated from
statistical analysis at 89 pounds of N/A.

Corn plantings at Quincy in 1966 compared tilther type planting with the conventional
approach (Table 5). No significant difference in yield due to method of planting wae
obtained. There was a significant response from up to 96 pounds of nitrogen c.dedressing
with both methods of planting.

Corn was planted at Marianna in both 1965 and 1966 in bermudagrass sod (Table 6). Only
15 inch strips were prepared when the tilther was used with the middle of the rows left
untouched. Dalapon was used in some treatments to retard grass growth while the corn crop
was growing. Atrazine plus 2,4-D was used to retard weed growth, especially in treatments
not receiving Dalapon. In 1965 not enough time was allowed after the application of
Dalapon and before the corn was planted and the corn was severely damaged. Damage was much
less severe where the land was worked for conventional planting. In 1966, six weeks were
allowed between Dalapon treatment and planting and no damage to the corn was observed.
Dalapon gave good grass control both years while atrazine gave rather good broadleaf and some
grass control. Cultivation assisted in the control of grass more than of broadleaf weeds.
Yield response in 1965 was difficult to evaluate since the dalapon damage was more severe
where soil was not worked. Stands were poor and seedling damage was serious where planted
with the tilther planter. In 1966 a better evaluation can be made since there was no
dalapon damage. Yields were consistently higher where conventional planting methods were
used. Yields were very close, however, where all methods of controlling the grass and
weed problem were applied. Since less than 1/2 of the total soil surface was disturbed,
using the tilther planter, it might be assumed that the grass and weed competition would
soon be severe if some chemical or mechanical method of weed control was not used.

Summary

Soybean yields from once-over planting have been about equal to those from conventional
planting at both Quincy and Marianna. In those tests where conventionally planted beans
have yielded slightly more than the once-over planted, it is doubtful if the increase in
yield would cover the increased planting costs.

Corn experiments at Quincy and Marianna would also indicate no difference in potential
yield due to method of planting. Even when used in established sod the tilther has shown
possibilities if the proper herbicides and weed control methods were used in combination.

All experiments to date indicate that the once-over type of planting operation does
have possibilities although data needs to be accumulated over a longer period of time in
order to draw valid conclusions. Over-all production costs can be reduced with a once-over
planting operation; therefore, some sacrifice in yield could be made if necessary without
reducing net profits.